Techno-economic feasibility study of a system for the transfer of refrigeration capacity from LNG regasification plants to industrial assets

Abstract

The recovery of cold energy during the regasification of Liquefied Natural Gas (LNG) has gained attention in recent years due to the fast growth of the LNG trade market and the increasing importance that governments are giving to energy efficiency and sustainability. Near 200 kWh/ton of LNG are potentially recoverable during the regasification process, but this energy is usually discarded when seawater or ambient air are used as heat source. Researchers have focused on the development of technologies for the use of this cold energy in the fields of air separation and cryogenic power generation. However, in some regasification plants the demand of natural gas is so low or so fluctuating that this kind of applications are economically unfeasible. This research focused on determining the techno-economic feasibility of a heat pump and a cold distribution system for the transfer of a fraction of the refrigeration capacity of LNG to industrial assets with low-temperature refrigeration demands located in the surroundings of the regasification plant. CO2 was selected as the heat transfer fluid that recirculates in a close loop between the cold users and the LNG site. A techno-economic model was implemented in Matlab taking the distance between the users and the LNG plant, and the refrigeration demand as the evaluation parameters. It was found that for a refrigeration demand of 20 MW the distance between the plants should be less than 1.2 km in order to make a project economically feasible.